US11617821B2 - Wound based sensor system with ambient atmosphere monitoring - Google Patents

Abstract

Systems, apparatuses, and methods for providing negative pressure and/or instillation fluids to a tissue site are disclosed. Some embodiments are illustrative of an apparatus or system for delivering negative-pressure and/or therapeutic solution of fluids to a tissue site, which can be used in conjunction with sensing properties of fluids extracted from a tissue site and/or instilled at a tissue site. For example, an apparatus may comprise a dressing interface or connector that includes a pH sensor, a humidity sensor, a temperature sensor and/or a pressure sensor embodied on a single pad within the connector and proximate the tissue site to provide data indicative of acidity, humidity, temperature and pressure. Such apparatus may further comprise an ambient port for providing the pressure sensor and the humidity sensor with access to the ambient environment providing readings relative to the atmospheric pressure and humidity.

Description

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional Patent Application No. 62/785,026, entitled “Wound Based Sensor System with Ambient Atmosphere Monitoring,” filed Dec. 26, 2018, which is incorporated herein by reference for all purposes.

TECHNICAL FIELD

The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to systems and methods for providing negative-pressure therapy with instillation of topical treatment solutions requiring access to the ambient environment.

BACKGROUND

Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. Treatment of wounds or other tissue with reduced pressure may be commonly referred to as “negative-pressure therapy,” but is also known by other names, including “negative-pressure wound therapy,” “reduced-pressure therapy,” “vacuum therapy,” “vacuum-assisted closure,” and “topical negative-pressure,” for example. Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro-deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound can be washed out with a stream of liquid solution, or a cavity can be washed out using a liquid solution for therapeutic purposes. These practices are commonly referred to as “irrigation” and “lavage” respectively. “Instillation” is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negative-pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.

While the clinical benefits of negative-pressure therapy and instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients.

BRIEF SUMMARY

New and useful systems, apparatuses, and methods for instilling fluid to a tissue site in a negative-pressure therapy environment are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter. Some embodiments are illustrative of an apparatus or system for delivering negative-pressure and therapeutic solution of fluids to a tissue site, which can be used in conjunction with sensing properties of wound exudates extracted from a tissue site. For example, an apparatus may include a pH sensor, a humidity sensor, a temperature sensor and a pressure sensor embodied on a single pad proximate the tissue site to provide data indicative of acidity, humidity, temperature and pressure. Such apparatus may further comprise an ambient port for providing the pressure sensor and the humidity sensor with access to the ambient environment providing readings relative to the atmospheric pressure and humidity.

In some embodiments, for example, an apparatus may include a dressing interface for connecting a source of fluids to a tissue interface and sensing properties of fluid at a tissue site. The dressing interface may comprise a housing having a body including a therapy cavity and a component chamber fluidly isolated from the therapy cavity, wherein the therapy cavity has an opening configured to be in fluid communication with the tissue interface. The dressing interface may further comprise a negative-pressure port fluidly coupled to the therapy cavity and adapted to be fluidly coupled to a negative-pressure source, and also an ambient port fluidly coupled to the component chamber and adapted to be fluidly coupled to an ambient environment. The dressing interface may further comprise a control device disposed within the component chamber and including a microprocessor. The dressing interface may further comprise at least one sensor electrically coupled to the microprocessor and having a sensing portion disposed within the therapy cavity and further having an ambient input fluidly coupled to the component chamber of the dressing interface.

In some embodiments, the at least one sensor may comprise at least one of a pressure sensor, a temperature sensor, and a humidity sensor. In some example embodiments, the dressing interface may further comprise a fluid conduit having a first end coupled to the ambient port and a second end, and further comprise a fluid connector having a connector port fluidly coupled to the second end and the ambient environment through an orifice in the fluid connector. In other example embodiments, the dressing interface may further comprise a fluid conduit having a first end coupled to the ambient port and a second end, wherein the second end is configured to terminate proximate a canister fluidly coupled to the therapy cavity and having an orifice configured to access the ambient environment. In yet other example embodiments, the dressing interface may further comprise a fluid conduit having a first end coupled to the ambient port and a second end, wherein the second end is configured to terminate within a canister fluidly coupled to the therapy cavity and having an orifice configured to access the ambient environment.

In some embodiments, the dressing interface may further comprise a vent port fluidly coupled to the therapy cavity and adapted to enable airflow into the therapy cavity. The dressing interface may further comprise an instillation port fluidly coupled to the therapy cavity and adapted to fluidly couple an instillation source to the tissue interface. The dressing interface may further comprise a first baffle disposed proximate the reduced-pressure port and a second baffle disposed proximate the installation port, both extending into the therapy cavity to direct the flow of fluids within the therapy cavity. The dressing interface may further comprise a temperature sensor and a humidity sensor, each sensor having a sensing portion disposed within the therapy cavity and electrically coupled to the microprocessor through the body of the housing. The sensing portion of the humidity sensor and the temperature sensor may be disposed proximate the instillation port.

Some embodiments are illustrative of applying negative-pressure to a tissue interface and sensing properties of fluid at a tissue site. In one example embodiment, the method may comprise positioning a dressing interface wherein the dressing interface comprises a housing having a body including a therapy cavity and a component chamber fluidly isolated from the therapy cavity, wherein the therapy cavity has an opening configured to be in fluid communication with the tissue interface. The dressing interface may further comprise a negative-pressure port fluidly coupled to the therapy cavity, an ambient port fluidly coupled to the component chamber, a control device disposed within the component chamber, and at least one sensor having a sensing portion disposed within the therapy cavity and coupled to the control device. The dressing interface may further comprise an ambient input fluidly coupled to the component chamber for providing the sensor access to the ambient environment. The method may further comprise applying negative pressure to the therapy cavity to draw fluids from the tissue interface and into the therapy cavity. The method may further comprise sensing properties of the ambient environment provided by the at least one sensor through the ambient input and the component chamber, and sensing properties of the fluids within the therapy cavity provided by the at least one sensor as compared to the properties of the ambient environment.

Some embodiments are illustrative of a method for applying fluids to a tissue interface and sensing a property of a fluid at a tissue site for treating the tissue site. For example, the method may comprise positioning a dressing interface on the tissue site, the dressing interface having a housing having a body including a therapy cavity and a component chamber fluidly isolated from the therapy cavity, the therapy cavity having an opening configured to be in fluid communication with the tissue interface, and a control device disposed within the component chamber. The method may further comprise providing the component chamber with access to the ambient environment through an ambient port to a sensor disposed within the therapy cavity and coupled to the control device. The method also comprises applying negative pressure to the therapy cavity through a negative-pressure port to draw fluids from the tissue interface and into the therapy cavity. The method may also comprise sensing the property of the fluid within the therapy cavity with the sensor, and then providing a property signal to the control device indicative of the property of the fluid relative to the corresponding property of the ambient environment.

Some other embodiments are illustrative of a method for applying fluids to a tissue interface and sensing properties of fluids at a tissue site for treating the tissue site. For example, the method may comprise positioning a dressing interface on the tissue site, wherein the dressing interface may have a housing including an outside surface and a therapy cavity having an opening configured to be in fluid communication with the tissue interface. The dressing interface may further comprise a reduced-pressure port fluidly coupled to the therapy cavity and adapted to fluidly couple a reduced-pressure source to the therapy cavity, an instillation port fluidly coupled to the therapy cavity and adapted to fluidly couple an instillation source to the therapy cavity, and a pH sensor and a pressure sensor disposed within the therapy cavity and each electrically coupled to a control device. The method may further comprise applying reduced pressure to the therapy cavity to draw fluids from the tissue interface and into the therapy cavity, and sensing pH and pressure properties of the fluids within the therapy cavity provided from the pressure sensor and the pH sensor. The method may further comprise instilling fluids into the therapy cavity to cleanse the pressure sensor and the pH sensor.

Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.1 is a functional block diagram of an example embodiment of a therapy system for providing negative-pressure including both instillation and venting capabilities in accordance with this specification;

FIG.2A is a graph illustrating an illustrative embodiment of pressure control modes for the negative-pressure and instillation therapy system ofFIG.1 wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a continuous pressure mode and an intermittent pressure mode that may be used for applying negative pressure in the therapy system;

FIG.2B is a graph illustrating an illustrative embodiment of another pressure control mode for the negative-pressure and instillation therapy system ofFIG.1 wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a dynamic pressure mode that may be used for applying negative pressure in the therapy system;

FIG.3 is a flow chart showing an illustrative embodiment of a therapy method for providing negative-pressure and instillation therapy for delivering treatment solutions to a dressing at a tissue site;

FIG.4 is a sectional side view of a first dressing interface comprising a housing and a wall disposed within the housing and forming a therapy cavity including sensors and a component cavity including electrical devices that may be associated with some example embodiments of the therapy system ofFIG.1 for providing negative pressure including both instillation and venting capabilities to the therapy cavity through a single conduit;

FIG.5A is a perspective top view of the first dressing interface ofFIG.4,FIG.5B is a side view of the first dressing interface ofFIG.4 disposed on a tissue site, andFIG.5C is an end view of the first dressing interface ofFIG.4 disposed on the tissue site;

FIG.6A is an assembly view of the first dressing interface ofFIG.4 comprising components of the housing and a first example embodiment of a sensor assembly including the wall, the sensors, and the electrical devices;

FIG.6B is a system block diagram of the sensors and electrical devices comprising the sensor assembly ofFIG.6A;

FIGS.7A,7B and7C are a top view, side view, and bottom view, respectively, of the sensor assembly ofFIG.6;

FIG.7D is a perspective top view of the sensor assembly of the sensor assembly ofFIG.6 including one example embodiment of a pH sensor;

FIG.8A is a perspective bottom view of the first dressing interface ofFIG.4, andFIG.8B is a bottom view of the first dressing interface ofFIG.4;

FIG.9A is a top view of a first embodiment of a pH sensor that may be used with the sensor assembly ofFIG.8D, andFIG.9B is a top view of a second embodiment of a pH sensor that may be used with the sensor assembly ofFIG.8D;

FIG.10A is a sectional side view of a second dressing interface comprising a housing and a wall disposed within the housing and forming a therapy cavity including sensors and a component cavity including electrical devices that may be associated with some example embodiments of the therapy system ofFIG.1 for providing negative pressure including instillation to the therapy cavity through separate ports;

FIG.10B is a sectional bottom view of the second dressing interface ofFIG.10A taken along theline10B-10B showing the sensors and baffles disposed within the therapy cavity;

FIG.11A is a sectional side view of a third dressing interface which is a modified version of the second dressing interface ofFIGS.10A and10B further comprising a third port for venting to the therapy cavity;

FIG.11B is a sectional bottom view of a third dressing interface ofFIG.11A taken along theline11B-11B showing the sensors and baffles disposed within the therapy cavity;

FIG.12 is a schematic diagram of a fluid conduit including an in-line connector that may be associated with some example embodiments of the dressing interfaces ofFIGS.1,4,10A and11A for providing negative pressure and/or instillation including access to the ambient environment provided to a component chamber of the dressing interfaces;

FIG.13A is a cross-sectional, schematic view of a first embodiment of the fluid conduit ofFIG.12 including a negative pressure lumen, a vent lumen, and an ambient lumen; and

FIG.13B is a cross-sectional, schematic view of a second embodiment of the fluid conduit ofFIG.12 including a negative pressure lumen, and instillation lumen, a vent lumen, and an ambient lumen.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The following description of example embodiments provides information that enables a person skilled in the art to make and use the subject matter set forth in the appended claims, but may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as should be recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness burns, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.

The present technology also provides negative pressure therapy devices and systems, and methods of treatment using such systems with antimicrobial solutions.FIG.1 is a simplified functional block diagram of an example embodiment of atherapy system100 that can provide negative-pressure therapy with instillation of treatment solutions in accordance with this specification. Thetherapy system100 may include a negative-pressure supply, and may include or be configured to be coupled to a distribution component, such as a dressing. In general, a distribution component may refer to any complementary or ancillary component configured to be fluidly coupled to a negative-pressure supply between a negative-pressure supply and a tissue site. A distribution component is preferably detachable, and may be disposable, reusable, or recyclable. For example, a dressing102 is illustrative of a distribution component that may be coupled to a negative-pressure source and other components. Thetherapy system100 may be packaged as a single, integrated unit such as a therapy system including all of the components shown inFIG.1 that are fluidly coupled to thedressing102. The therapy system may be, for example, a V.A.C. Ulta™ System available from Kinetic Concepts, Inc. of San Antonio, Tex.

The dressing102 may be fluidly coupled to a negative-pressure source104. A dressing may include a cover, a tissue interface, or both in some embodiments. The dressing102, for example, may include acover106, a dressinginterface107, and atissue interface108. A computer or a controller device, such as acontroller110, may also be coupled to the negative-pressure source104. In some embodiments, thecover106 may be configured to cover thetissue interface108 and the tissue site, and may be adapted to seal the tissue interface and create a therapeutic environment proximate to a tissue site for maintaining a negative pressure at the tissue site. In some embodiments, the dressinginterface107 may be configured to fluidly couple the negative-pressure source104 to the therapeutic environment of the dressing. Thetherapy system100 may optionally include a fluid container, such as acontainer112, fluidly coupled to the dressing102 and to the negative-pressure source104.

Thetherapy system100 may also include a source of instillation solution, such as asolution source114. A distribution component may be fluidly coupled to a fluid path between a solution source and a tissue site in some embodiments. For example, aninstillation pump116 may be coupled to thesolution source114, as illustrated in the example embodiment ofFIG.1. Theinstillation pump116 may also be fluidly coupled to the negative-pressure source104 such as, for example, by afluid conductor119. In some embodiments, theinstillation pump116 may be directly coupled to the negative-pressure source104, as illustrated inFIG.1, but may be indirectly coupled to the negative-pressure source104 through other distribution components in some embodiments. For example, in some embodiments, theinstillation pump116 may be fluidly coupled to the negative-pressure source104 through the dressing102. In some embodiments, theinstillation pump116 and the negative-pressure source104 may be fluidly coupled to two different locations on thetissue interface108 by two different dressing interfaces. For example, the negative-pressure source104 may be fluidly coupled to thedressing interface107 while theinstillation pump116 may be fluidly to the coupled to dressinginterface107 or asecond dressing interface117. In some other embodiments, theinstillation pump116 and the negative-pressure source104 may be fluidly coupled to two different tissue interfaces by two different dressing interfaces, one dressing interface for each tissue interface (not shown).

Thetherapy system100 also may include sensors to measure operating parameters and provide feedback signals to thecontroller110 indicative of the operating parameters properties of fluids extracted from a tissue site. As illustrated inFIG.1, for example, thetherapy system100 may include apressure sensor120, anelectric sensor124, or both, coupled to thecontroller110. Thepressure sensor120 may be fluidly coupled or configured to be fluidly coupled to a distribution component such as, for example, the negative-pressure source104 either directly or indirectly through thecontainer112. Thepressure sensor120 may be configured to measure pressure being generated by the negative-pressure source104, i.e., the pump pressure (PP). Theelectric sensor124 also may be coupled to the negative-pressure source104 to measure the pump pressure (PP). In some example embodiments, theelectric sensor124 may be fluidly coupled proximate the output of the output of the negative-pressure source104 to directly measure the pump pressure (PP). In other example embodiments, theelectric sensor124 may be electrically coupled to the negative-pressure source104 to measure the changes in the current in order to determine the pump pressure (PP).

Distribution components may be fluidly coupled to each other to provide a distribution system for transferring fluids (i.e., liquid and/or gas). For example, a distribution system may include various combinations of fluid conductors and fittings to facilitate fluid coupling. A fluid conductor generally includes any structure with one or more lumina adapted to convey a fluid between two ends, such as a tube, pipe, hose, or conduit. Typically, a fluid conductor is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Some fluid conductors may be molded into or otherwise integrally combined with other components. A fitting can be used to mechanically and fluidly couple components to each other. For example, a fitting may comprise a projection and an aperture. The projection may be configured to be inserted into a fluid conductor so that the aperture aligns with a lumen of the fluid conductor. A valve is a type of fitting that can be used to control fluid flow. For example, a check valve can be used to substantially prevent return flow. A port is another example of a fitting. A port may also have a projection, which may be threaded, flared, tapered, barbed, or otherwise configured to provide a fluid seal when coupled to a component.

In some embodiments, distribution components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material. Coupling may also include mechanical, thermal, electrical, or chemical coupling (such as a chemical bond) in some contexts. For example, a tube may mechanically and fluidly couple the dressing102 to thecontainer112 in some embodiments. In general, components of thetherapy system100 may be coupled directly or indirectly. For example, the negative-pressure source104 may be directly coupled to thecontroller110, and may be indirectly coupled to thedressing interface107 through thecontainer112 byconduit126 andconduit135, also referred to herein asnegative pressure conduit126 andnegative pressure conduit135. Thepressure sensor120 may be fluidly coupled to the dressing102 directly (not shown) or indirectly through thecontainer112 and afilter122 byconduit121 andconduit155. Thefilter122 may be any type of filter for preventing the ingress of liquids from thecontainer112. Additionally, theinstillation pump116 may be coupled indirectly to thedressing interface107 through thesolution source114 and aninstillation regulator115 byfluid conductors132 and133, also referred to herein asinstillation conduit133. Theinstillation regulator115 may be electrically coupled to the controller110 (not shown) that may be programmed along with theinstillation pump116 to deliver instillation fluid in a controlled fashion. Alternatively, theinstillation pump116 may be coupled indirectly to thesecond dressing interface117 through thesolution source114 and theinstillation regulator115 byinstillation conduits133 and134.

Some embodiments of thetherapy system100 may include a solution source, such assolution source114, without an instillation pump, such as theinstillation pump116. Instead, thesolution source114 may be fluidly coupled directly or indirectly to thedressing interface107 and may further include theinstillation regulator115 electrically coupled to thecontroller110 as described above. In operation, thenegative pressure source104 may apply negative pressure to thedressing interface107 through thecontainer112 and thenegative pressure conduit135 to create a vacuum within the spaces formed by the dressinginterface107 and thetissue interface108. The vacuum within the spaces would draw instillation fluid into the spaces for cleansing or providing therapy treatment to the tissue site. In some embodiments, thecontroller110 may be programmed to modulate theinstillation regulator115 to control the flow of instillation fluid into the spaces. In another example embodiment, thetherapy system100 may include both theinstillation pump116 and thenegative pressure source104 to alternately deliver instillation fluid to thedressing interface107 by providing a positive pressure to thesolution source114 and a negative pressure directly to thedressing interface107, respectively. Any of the embodiments described above may be utilized to periodically clean, rinse, or hydrate the tissue site using saline along with other pH-modulating instillation fluids such as weak acidic acids.

The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example.

In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies something in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” implies something relatively further away from a source of negative pressure or closer to a source of positive pressure. Similarly, it may be convenient to describe certain features in terms of fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein. However, the fluid path may also be reversed in some applications (such as by substituting a positive-pressure source for a negative-pressure source) and this descriptive convention should not be construed as a limiting convention.

“Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment provided by the dressing102. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. Similarly, references to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure applied to a tissue site may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between −5 mm Hg (−667 Pa) and −500 mm Hg (−66.7 kPa). Common therapeutic ranges are between −75 mm Hg (−9.9 kPa) and −300 mm Hg (−39.9 kPa).

A negative-pressure supply, such as the negative-pressure source104, may be a reservoir of air at a negative pressure, or may be a manual or electrically-powered device that can reduce the pressure in a sealed volume, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro-pump, for example. A negative-pressure supply may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate therapy. For example, in some embodiments, the negative-pressure source104 may be combined with thecontroller110 and other components into a therapy unit. A negative-pressure supply may also have one or more supply ports configured to facilitate coupling and de-coupling the negative-pressure supply to one or more distribution components.

Thetissue interface108 can be generally adapted to contact a tissue site. Thetissue interface108 may be partially or fully in contact with the tissue site. If the tissue site is a wound, for example, thetissue interface108 may partially or completely fill the wound, or may be placed over the wound. Thetissue interface108 may take many forms, and may have many sizes, shapes, or thicknesses depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site. For example, the size and shape of thetissue interface108 may be adapted to the contours of deep and irregular shaped tissue sites. Moreover, any or all of the surfaces of thetissue interface108 may have projections or an uneven, course, or jagged profile that can induce strains and stresses on a tissue site, which can promote granulation at the tissue site.

In some embodiments, thetissue interface108 may be a manifold such asmanifold408 shown inFIG.4. A “manifold” in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across a tissue site, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid across a tissue site.

In some illustrative embodiments, the pathways of a manifold may be interconnected to improve distribution or collection of fluids across a tissue site. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores. For example, cellular foam, open-cell foam, reticulated foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid channels. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

The average pore size of a foam manifold may vary according to needs of a prescribed therapy. For example, in some embodiments, thetissue interface108 may be a foam manifold having pore sizes in a range of 400-600 microns. The tensile strength of thetissue interface108 may also vary according to needs of a prescribed therapy. For example, the tensile strength of a foam may be increased for instillation of topical treatment solutions. In one non-limiting example, thetissue interface108 may be an open-cell, reticulated polyurethane foam such as GranuFoam® dressing or VeraFlo® foam, both available from Kinetic Concepts, Inc. of San Antonio, Tex.

Thetissue interface108 may be either hydrophobic or hydrophilic. In an example in which thetissue interface108 may be hydrophilic, thetissue interface108 may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of thetissue interface108 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic foam is a polyvinyl alcohol, open-cell foam such as V.A.C. WhiteFoam® dressing available from Kinetic Concepts, Inc. of San Antonio, Tex. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

Thetissue interface108 may further promote granulation at a tissue site when pressure within the sealed therapeutic environment is reduced. For example, any or all of the surfaces of thetissue interface108 may have an uneven, coarse, or jagged profile that can induce microstrains and stresses at a tissue site if negative pressure is applied through thetissue interface108.

In some embodiments, thetissue interface108 may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include without limitation polycarbonates, polyfumarates, and capralactones. Thetissue interface108 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with thetissue interface108 to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

In some embodiments, thecover106 may provide a bacterial barrier and protection from physical trauma. Thecover106 may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. Thecover106 may be, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. Thecover106 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 300 g/m{circumflex over ( )}2 per twenty-four hours in some embodiments. In some example embodiments, thecover106 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. In some embodiments, the cover may be a drape such asdrape406 shown inFIG.4.

An attachment device may be used to attach thecover106 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure-sensitive adhesive that extends about a periphery, a portion, or an entire sealing member. In some embodiments, for example, some or all of thecover106 may be coated with an acrylic adhesive having a coating weight between 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

In some embodiments, the dressinginterface107 may facilitate coupling the negative-pressure source104 to thedressing102. The negative pressure provided by the negative-pressure source104 may be delivered through theconduit135 to a negative-pressure interface, which may include an elbow portion. In one illustrative embodiment, the negative-pressure interface may be a T.R.A.C.® Pad or Sensa T.R.A.C.® Pad available from KCI of San Antonio, Tex. The negative-pressure interface enables the negative pressure to be delivered through thecover106 and to thetissue interface108 and the tissue site. In this illustrative, non-limiting embodiment, the elbow portion may extend through thecover106 to thetissue interface108, but numerous arrangements are possible.

A controller, such as thecontroller110, may be a microprocessor or computer programmed to operate one or more components of thetherapy system100, such as the negative-pressure source104. In some embodiments, for example, thecontroller110 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of thetherapy system100. Operating parameters may include the power applied to the negative-pressure source104, the pressure generated by the negative-pressure source104, or the pressure distributed to thetissue interface108, for example. Thecontroller110 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.

Sensors, such as thepressure sensor120 or theelectric sensor124, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured. For example, thepressure sensor120 and theelectric sensor124 may be configured to measure one or more operating parameters of thetherapy system100. In some embodiments, thepressure sensor120 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, thepressure sensor120 may be a piezoresistive strain gauge. Theelectric sensor124 may optionally measure operating parameters of the negative-pressure source104, such as the voltage or current, in some embodiments. Preferably, the signals from thepressure sensor120 and theelectric sensor124 are suitable as an input signal to thecontroller110, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by thecontroller110. Typically, the signal is an electrical signal that is transmitted and/or received on by wire or wireless means, but may be represented in other forms, such as an optical signal.

Thesolution source114 is representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions. Examples of such other therapeutic solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions. In one illustrative embodiment, thesolution source114 may include a storage component for the solution and a separate cassette for holding the storage component and delivering the solution to thetissue site150, such as a V.A.C. VeraLink™ Cassette available from Kinetic Concepts, Inc. of San Antonio, Tex.

Thecontainer112 may also be representative of a container, canister, pouch, or other storage component, which can be used to collect and manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container such as, for example, a container162, may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy. In some embodiments, thecontainer112 may comprise a canister having a collection chamber, a first inlet fluidly coupled to the collection chamber and a first outlet fluidly coupled to the collection chamber and adapted to receive negative pressure from a source of negative pressure. In some embodiments, a first fluid conductor may comprise a first member such as, for example, theconduit135 fluidly coupled between the first inlet and thetissue interface108 by the negative-pressure interface described above, and a second member such as, for example, theconduit126 fluidly coupled between the first outlet and a source of negative pressure whereby the first conductor is adapted to provide negative pressure within the collection chamber to the tissue site.

Thetherapy system100 may also comprise a flow regulator such as, for example, avent regulator118 fluidly coupled to a source of ambient air to provide a controlled or managed flow of ambient air to the sealed therapeutic environment provided by the dressing102 and ultimately the tissue site. In some embodiments, thevent regulator118 may control the flow of ambient fluid to purge fluids and exudates from the sealed therapeutic environment. In some embodiments, thevent regulator118 may be fluidly coupled by a fluid conductor or ventconduit145 through the dressinginterface107 to thetissue interface108. Thevent regulator118 may be configured to fluidly couple thetissue interface108 to a source of ambient air as indicated by a dashed arrow. In some embodiments, thevent regulator118 may be disposed within thetherapy system100 rather than being proximate to the dressing102 so that the air flowing through thevent regulator118 is less susceptible to accidental blockage during use. In such embodiments, thevent regulator118 may be positioned proximate thecontainer112 and/or proximate a source of ambient air where thevent regulator118 is less likely to be blocked during usage.

In operation, thetissue interface108 may be placed within, over, on, or otherwise proximate a tissue site, such astissue site150. Thecover106 may be placed over thetissue interface108 and sealed to an attachment surface near thetissue site150. For example, thecover106 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing102 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source104 can reduce the pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through thetissue interface108 in the sealed therapeutic environment can induce macrostrain and microstrain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected incontainer112.

In one embodiment, thecontroller110 may receive and process data, such as data related to the pressure distributed to thetissue interface108 from thepressure sensor120. Thecontroller110 may also control the operation of one or more components oftherapy system100 to manage the pressure distributed to thetissue interface108 for application to the wound at thetissue site150, which may also be referred to as the wound pressure (WP). In one embodiment,controller110 may include an input for receiving a desired target pressure (TP) set by a clinician or other user and may be program for processing data relating to the setting and inputting of the target pressure (TP) to be applied to thetissue site150. In one example embodiment, the target pressure (TP) may be a fixed pressure value determined by a user/caregiver as the reduced pressure target desired for therapy at thetissue site150 and then provided as input to thecontroller110. The user may be a nurse or a doctor or other approved clinician who prescribes the desired negative pressure to which thetissue site150 should be applied. The desired negative pressure may vary from tissue site to tissue site based on the type of tissue forming thetissue site150, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting the desired target pressure (TP), the negative-pressure source104 is controlled to achieve the target pressure (TP) desired for application to thetissue site150.

Referring more specifically toFIG.2A, a graph illustrating an illustrative embodiment ofpressure control modes200 that may be used for the negative-pressure and instillation therapy system ofFIG.1 is shown wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a continuous pressure mode and an intermittent pressure mode that may be used for applying negative pressure in the therapy system. The target pressure (TP) may be set by the user in a continuous pressure mode as indicated bysolid line201 and dottedline202 wherein the wound pressure (WP) is applied to thetissue site150 until the user deactivates the negative-pressure source104. The target pressure (TP) may also be set by the user in an intermittent pressure mode as indicated bysolid lines201,203 and205 wherein the wound pressure (WP) is cycled between the target pressure (TP) and atmospheric pressure. For example, the target pressure (TP) may be set by the user at a value of 125 mmHg for a specified period of time (e.g., 5 min) followed by the therapy being turned off for a specified period of time (e.g., 2 min) as indicated by the gap between thesolid lines203 and205 by venting thetissue site150 to the atmosphere, and then repeating the cycle by turning the therapy back on as indicated bysolid line205 which consequently forms a square wave pattern between the target pressure (TP) level and atmospheric pressure. In some embodiments, the ratio of the “on-time” to the “off-time” or the total “cycle time” may be referred to as a pump duty cycle (PD).

In some example embodiments, the decrease in the wound pressure (WP) at thetissue site150 from ambient pressure to the target pressure (TP) is not instantaneous, but rather gradual depending on the type of therapy equipment and dressing being used for the particular therapy treatment. For example, the negative-pressure source104 and the dressing102 may have an initial rise time as indicated by the dashedline207 that may vary depending on the type of dressing and therapy equipment being used. For example, the initial rise time for one therapy system may be in the range between about 20-30 mmHg/second or, more specifically, equal to about 25 mmHg/second, and in the range between about 5-10 mmHg/second for another therapy system. When thetherapy system100 is operating in the intermittent mode, the repeating rise time as indicated by thesolid line205 may be a value substantially equal to the initial rise time as indicated by the dashedline207.

The target pressure may also be a variable target pressure (VTP) controlled or determined bycontroller110 that varies in a dynamic pressure mode. For example, the variable target pressure (VTP) may vary between a maximum and minimum pressure value that may be set as an input determined by a user as the range of negative pressures desired for therapy at thetissue site150. The variable target pressure (VTP) may also be processed and controlled bycontroller110 that varies the target pressure (TP) according to a predetermined waveform such as, for example, a sine waveform or a saw-tooth waveform or a triangular waveform, that may be set as an input by a user as the predetermined or time-varying reduced pressures desired for therapy at thetissue site150.

Referring more specifically toFIG.2B, a graph illustrating an illustrative embodiment of another pressure control mode for the negative-pressure and instillation therapy system ofFIG.1 is shown wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a dynamic pressure mode that may be used for applying negative pressure in the therapy system. For example, the variable target pressure (VTP) may be a reduced pressure that provides an effective treatment by applying reduced pressure totissue site150 in the form of a triangular waveform varying between a minimum and maximum pressure of 50-125 mmHg with arise time212 set at a rate of +25 mmHg/min. and adescent time211 set at −25 mmHg/min, respectively. In another embodiment of thetherapy system100, the variable target pressure (VTP) may be a reduced pressure that applies reduced pressure totissue site150 in the form of a triangular waveform varying between 25-125 mmHg with arise time212 set at a rate of +30 mmHg/min and adescent time211 set at −30 mmHg/min. Again, the type of system and tissue site determines the type of reduced pressure therapy to be used.

FIG.3 is a flow chart illustrating an illustrative embodiment of atherapy method300 that may be used for providing negative-pressure and instillation therapy for delivering an antimicrobial solution or other treatment solution to a dressing at a tissue site. In one embodiment, thecontroller110 receives and processes data, such as data related to fluids provided to thetissue interface108. Such data may include the type of instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to the tissue site (“fill volume”), and the amount of time needed to soak the tissue interface (“soak time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the soak time may be between one second to 30 minutes. Thecontroller110 may also control the operation of one or more components of thetherapy system100 to manage the instillation fluids delivered from thesolution source114 to thetissue site150 for cleaning and/or providing therapy treatment to the wound along with the negative pressure therapy as described above. In one embodiment, fluid may be instilled to thetissue site150 by applying a negative pressure from the negative-pressure source104 to reduce the pressure at thetissue site150 and draw the instillation fluid into the dressing102 as indicated at302 and described above in more detail. In another embodiment, fluid may be instilled to thetissue site150 by applying a positive pressure from the negative-pressure source104 (not shown) or theinstillation pump116 to force the instillation fluid from thesolution source114 to thetissue interface108 as indicated at304. In yet another embodiment, fluid may be instilled to thetissue site150 by elevating thesolution source114 to height sufficient to force the instillation fluid into thetissue interface108 by the force of gravity as indicated at306. Thus, thetherapy method300 includes instilling fluid into thetissue interface108 by either drawing or forcing the fluid into thetissue interface108 as indicated at310.

Thetherapy method300 may control the fluid dynamics of applying the fluid solution to thetissue interface108 at312 by providing a continuous flow of fluid at314 or an intermittent flow of fluid for soaking thetissue interface108 at316. Thetherapy method300 may include the application of negative pressure to thetissue interface108 to provide either the continuous flow or intermittent soaking flow of fluid at320. The application of negative pressure may be implemented to provide a continuous pressure mode of operation at322 as described above to achieve a continuous flow rate of instillation fluid through thetissue interface108 or a dynamic pressure mode of operation at324 as described above to vary the flow rate of instillation fluid through thetissue interface108. Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation at326 as described above to allow instillation fluid to soak into thetissue interface108 as described above. In the intermittent mode, a specific fill volume and the soak time may be provided depending, for example, on the type of wound being treated and the type of dressing102 being utilized to treat the wound. After or during instillation of fluid into thetissue interface108 has been completed, thetherapy method300 may begin may be utilized using any one of the three modes of operation at330 as described above. Thecontroller110 may be utilized to select any one of these three modes of operation and the duration of the negative pressure therapy as described above before commencing another instillation cycle at340 by instilling more fluid at310.

As discussed above, thetissue site150 may include, without limitation, any irregularity with a tissue, such as an open wound, surgical incision, or diseased tissue. Thetherapy system100 is presented in the context of a tissue site that includes a wound that may extend through the epidermis and the dermis, and may reach into the hypodermis or subcutaneous tissue. Thetherapy system100 may be used to treat a wound of any depth, as well as many different types of wounds including open wounds, incisions, or other tissue sites. Thetissue site150 may be the bodily tissue of any human, animal, or other organism, including bone tissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, ligaments, or any other tissue. Treatment of thetissue site150 may include removal of fluids originating from thetissue site150, such as exudates or ascites, or fluids instilled into the dressing to cleanse or treat thetissue site150, such as antimicrobial solutions.

As indicated above, thetherapy system100 may be packaged as a single, integrated unit such as a therapy system including all of the components shown inFIG.1 that are fluidly coupled to thedressing102. In some embodiments, an integrated therapy unit may include the negative-pressure source104, thecontroller110, thepressure sensor120, and thecontainer112 which may be fluidly coupled to thedressing interface107. In this therapy unit, the negative-pressure source104 is indirectly coupled to thedressing interface107 through thecontainer112 byconduit126 andconduit135, and thepressure sensor120 is indirectly coupled to thedressing interface107 byconduit121 andconduit155 as described above. In some embodiments, thenegative pressure conduit135 and thepressure sensing conduit155 may be combined in a single fluid conductor that can be, for example, a multi-lumen tubing comprising a central primary lumen that functions as thenegative pressure conduit135 for delivering negative pressure to thedressing interface107 and several peripheral auxiliary lumens that function as thepressure sensing conduit155 for sensing the pressure that the dressinginterface107 delivers to thetissue interface108. In this type of therapy unit wherein thepressure sensor120 is removed from and indirectly coupled to thedressing interface107, the negative pressure measured by thepressure sensor120 may be different from the wound pressure (WP) actually being applied to thetissue site150. Such pressure differences must be approximated in order to adjust the negative-pressure source104 to deliver the pump pressure (PP) necessary to provide the desired or target pressure (TP) to thetissue interface108. Moreover, such pressure differences and predictability may be exacerbated by viscous fluids such as exudates being produced by the tissue site or utilizing a single therapy device including a pressure sensor to deliver negative pressure to multiple tissue sites on a single patient.

What is needed is a pressure sensor that is integrated within the dressinginterface107 so that the pressure sensor is proximate thetissue interface108 when disposed on the tissue site in order to provide a more accurate reading of the wound pressure (WP) being provided within the therapy environment of thedressing102. The integrated pressure sensor may be used with or without theremote pressure sensor120 that is indirectly coupled to thedressing interface107. In some example embodiments, the dressinginterface107 may comprise a housing having a therapy cavity that opens to the tissue site when positioned thereon. The integrated pressure sensor may have a sensing portion disposed within the therapy cavity along with other sensors including, for example, a temperature sensor, a humidity sensor, and a pH sensor. The sensors may be electrically coupled to thecontroller110 outside the therapy cavity to provide data indicative of the pressure, temperature, humidity, and acidity properties within the therapeutic space of the therapy cavity. The sensors may be electrically coupled to thecontroller110, for example, by wireless means. Systems, apparatuses, and methods described herein provide the advantage of more accurate measurements of these properties, as well as other significant advantages described below in more detail.

As indicated above, the dressing102 may include thecover106, the dressinginterface107, and thetissue interface108. Referring now toFIGS.4,5A,5B,5C,6A,6B, and7, a first dressing is shown comprising adressing interface400, a cover ordrape406, and a tissue interface ormanifold408 disposed adjacent atissue site410, all of which may be functionally similar in part to thedressing interface107, thecover106, and thetissue interface108, respectively, as described above. In one example embodiment, the dressinginterface400 may comprise ahousing401 and awall402 disposed within thehousing401 wherein thewall402 forms a recessed space or atherapy cavity403 that opens to the manifold408 when disposed at thetissue site410 and acomponent cavity404 opening away from thetissue site410 of the upper portion of the dressinginterface400. In some embodiments, sensing portions of various sensors may be disposed within thetherapy cavity403, and electrical devices associated with the sensors may be disposed within thecomponent cavity404 and electrically coupled to the sensing portions through thewall402. Electrical devices disposed within thecomponent cavity404 may include components associated with some example embodiments of the therapy system ofFIG.1. Although thedressing interface400 and thetherapy cavity403 are functionally similar to thedressing interface107 as described above, the dressinginterface400 further comprises thewall402, the sensors, and the associated electrical devices described below in more detail. In some embodiments, thehousing401 may further comprise a neck portion orneck407 fluidly coupled to aconduit405. In some embodiments, thehousing401 may further comprise a flange portion orflange409 having flow channels (seeFIG.8) configured to be fluidly coupled to thetherapy cavity403 when disposed on themanifold408.

In some example embodiments, theneck407 of thehousing401 may include portions of both thetherapy cavity403 and thecomponent cavity404. That portion of theneck407 extending into thetherapy cavity403 is fluidly coupled to theconduit405, while the portion extending into thecomponent cavity404 may contain some of the electrical devices. In some example embodiments, theconduit405 may comprise a primary lumen or anegative pressure lumen430 and separate auxiliary lumens such as, for example, aninstillation lumen433 and aventing lumen435 fluidly coupled by theneck407 of thehousing401 to thetherapy cavity403. Thenegative pressure lumen430 is similar to thenegative pressure conduit135 that may be coupled indirectly to the negative-pressure source104. Theventing lumen435 is similar to thevent conduit145 that may be fluidly coupled to thevent regulator118 for purging fluids from thetherapy cavity403. Theinstillation lumen433 is similar to theinstillation conduit133 that may be fluidly coupled directly or indirectly to thesolution source114 for flushing fluids from thetherapy cavity403 for removal by the application of negative pressure through thenegative pressure lumen430.

In some embodiments, thecomponent cavity404 containing the electrical devices may be open to the ambient environment such that the electrical devices are exposed to the ambient environment. In other example embodiments, thecomponent cavity404 may be closed by a cover such as, for example, acap411 to protect the electrical devices. In still other embodiments, thecomponent cavity404 covered by thecap411 may still be vented to the ambient environment to provide cooling to the electrical devices and a source of ambient pressure for a pressure sensor disposed in thetherapy cavity403 as described in more detail below. Thefirst dressing interface400 may further comprise adrape ring413 covering the circumference of theflange409 and the adjacent portion of thedrape406 to seal thetherapy cavity403 of thehousing401 over the manifold408 and thetissue site410. In some embodiments, thedrape ring413 may comprise a polyurethane film including and an attachment device such as, for example, an acrylic, polyurethane gel, silicone, or hybrid combination of the foregoing adhesives (not shown) to attach thedrape ring413 to theflange409 and thedrape406. The attachment device ofdrape ring413 may be a single element of silicon or hydrocolloid with the adhesive on each side that functions as a gasket between thedrape406 and theflange409. In some embodiments, thedrape ring413 may be similar to thecover106 and/or the attachment device described above in more detail.

In some embodiments, apressure sensor416, a temperature andhumidity sensor418, and a pH sensor420 (collectively referred to below as “the sensors”) may be disposed in thehousing401 with each one having a sensing portion extending into thetherapy cavity403 of thehousing401 and associated electronics disposed within thecomponent cavity404. Thehousing401 may include other types of sensors, or combinations of the foregoing sensors, such as, for example, oxygen sensors. In some example embodiments, the sensors may be coupled to or mounted on thewall402 and electrically coupled to electrical components and circuits disposed within thecomponent cavity404 by electrical conductors extending through thewall402. In some preferred embodiments, the electrical conductors extend through pathways in thewall402 while keeping thetherapy cavity403 electrically and pneumatically isolated from thecomponent cavity404. For example, thewall402 may comprise acircuit board432 on which the electrical circuits and/or components may be printed or mounted. In some other examples, thecircuit board432 may be thewall402 that covers an opening between thetherapy cavity403 and thecomponent cavity404, and pneumatically seals thetherapy cavity403 from thecomponent cavity404 when seated over the opening.

In some embodiments, the electrical circuits and/or components associated with the sensors that are mounted on thecircuit board432 within thecomponent cavity404 may be electrically coupled to thecontroller110 to interface with the rest of thetherapy system100 as described above. In some embodiments, for example, the electrical circuits and/or components may be electrically coupled to thecontroller110 by a conductor that may be a component of theconduit405. In some other preferred embodiments, acommunications module422 may be disposed in thecomponent cavity404 of thehousing401 and mounted on thecircuit board432 within thecomponent cavity404. Using awireless communications module422 has the advantage of eliminating an electrical conductor between the dressinginterface400 and the integrated portion of thetherapy system100 that may become entangled with theconduit405 when in use during therapy treatments. For example, the electrical circuits and/or components associated with the sensors along with the terminal portion of the sensors may be electrically coupled to thecontroller110 by wireless means such as an integrated device implementing Bluetooth® Low Energy wireless technology. More specifically, thecommunications module422 may be a Bluetooth® Low Energy system-on-chip that includes a microprocessor (an example of the microprocessors referred to hereinafter) such as the nRF51822 chip available from Nordic Semiconductor. Thewireless communications module422 may be implemented with other wireless technologies suitable for use in the medical environment.

In some embodiments, avoltage regulator423 for signal conditioning and apower source424 may be disposed within thecomponent cavity404 of thehousing401, and mounted on thecircuit board432. Thepower source424 may be secured to thecircuit board432 by abracket426. Thepower source424 may be, for example, a battery that may be a coin battery having a low-profile that provides a 3-volt source for thecommunications module422 and the other electronic components within thecomponent cavity404 associated with the sensors. In some example embodiments, the sensors, the electrical circuits and/or components associated with the sensors, thewall402 and/or thecircuit board432, thecommunications module422, and thepower source424 may be integrated into a single package and referred to hereinafter as asensor assembly425 as shown inFIG.6B. In some preferred embodiments, thewall402 of thesensor assembly425 may be thecircuit board432 itself as described above that provides a seal betweentissue site410 and the atmosphere when positioned over the opening between thetherapy cavity403 and thecomponent cavity404 of thehousing401 and functions as thewall402 within thehousing401 that forms thetherapy cavity403.

Referring now toFIGS.8A and8B, a perspective view and a bottom view, respectively, of a bottom surface of theflange409 facing the manifold408 is shown. In some embodiments, the bottom surface may comprise features or channels to direct the flow of liquids and/or exudates away from the sensors out of thetherapy cavity403 into thenegative pressure lumen430 when negative pressure is being applied to thetherapy cavity403. In some embodiments, these channels may be molded into the bottom surface of theflange409 to form a plurality ofserrated guide channels437,perimeter collection channels438, andintermediate collection channels439. Theserrated guide channels437 may be positioned and oriented in groups on bottom surface to directly capture and channel at least half of the liquids being drawn into thetherapy cavity403 with the groups ofserrated guide channels437, and indirectly channel a major portion of the balance of the liquids being drawn into thetherapy cavity403 between the groups ofserrated guide channels437. In addition,perimeter collection channels438 andintermediate collection channels439 redirect the flow of liquids that are being drawn in between the groups of radially-orientedserrated guide channels437 into theguide channels437. An example of this redirected flow is illustrated bybolded flow arrows436. In some example embodiments, a portion of thehousing401 within thetherapy cavity403 may comprise a second set ofserrated guide channels427 spaced apart and radially-oriented to funnel liquids being drawn into thetherapy cavity403 from theflange409 into thenegative pressure lumen430. In other example embodiments of the bottom surface of theflange409 and that portion of thehousing401 within thetherapy cavity403, the channels may be arranged in different patterns.

As indicated above, thesensor assembly425 may comprise apressure sensor416, ahumidity sensor418, a temperature sensor as a component of either thepressure sensor416 or thehumidity sensor418, and apH sensor420. Each of the sensors may comprise a sensing portion extending into thetherapy cavity403 of thehousing401 and a terminal portion electrically coupled to the electrical circuits and/or components within thecomponent cavity404. Referring more specifically toFIGS.4,6A,6B, and7A-7D, thehousing401 may comprise asensor bracket441 that may be a molded portion of thehousing401 within thetherapy cavity403 in some embodiments. Thesensor bracket441 may be structured to house and secure thepressure sensor416 on thecircuit board432 within thetherapy cavity403 of thesensor assembly425 that provides a seal betweentissue site410 and the atmosphere as described above. In some embodiments, thepressure sensor416 may be a differential gauge comprising asensing portion442 and a terminal portion or vent443. Thevent443 of thepressure sensor416 may be fluidly coupled through thecircuit board432 to thecomponent cavity404 and the atmosphere by avent hole444 extending through thecircuit board432. Because thecomponent cavity404 is vented to the ambient environment, thevent443 of thepressure sensor416 is able to measure the wound pressure (WP) with reference to the ambient pressure. Thesensing portion442 of thepressure sensor416 may be positioned in close proximity to the manifold408 to optimize fluid coupling and accurately measure the wound pressure (WP) at thetissue site410. In some embodiments, thepressure sensor416 may be a piezo-resistive pressure sensor having a pressure sensing element covered by a dielectric gel such as, for example, a Model TE1620 pressure sensor available from TE Connectivity. The dielectric gel provides electrical and fluid isolation from the blood and wound exudates in order to protect the sensing element from corrosion or other degradation. This allows thepressure sensor416 to measure the wound pressure (WP) directly within thetherapy cavity403 of thehousing401 proximate to the manifold408 as opposed to measuring the wound pressure (WP) from a remote location. In some embodiments, thepressure sensor416 may be a gauge that measures the absolute pressure that does not need to be vented.

In some embodiments, thepressure sensor416 also may comprise a temperature sensor for measuring the temperature at thetissue site410. In other embodiments, thehumidity sensor418 may comprise a temperature sensor for measuring the temperature at thetissue site410. Thesensor bracket441 also may be structured to support thehumidity sensor418 on thecircuit board432 of thesensor assembly425. In some embodiments, thehumidity sensor418 may comprise a sensing portion that is electrically coupled through thecircuit board432 to a microprocessor mounted on the other side of thecircuit board432 within thecomponent cavity404. The sensing portion of thehumidity sensor418 may be fluidly coupled to the space within thetherapy cavity403 that includes afluid pathway445 extending from thetherapy cavity403 into thenegative pressure lumen430 of theconduit405 as indicated by the bold arrow to sense both the humidity and the temperature. The sensing portion of thehumidity sensor418 may be positioned within thefluid pathway445 to limit direct contact with bodily fluids being drawn into thenegative pressure lumen430 from thetissue site410. In some embodiments, the space within thetherapy cavity403 adjacent the sensing portion of thehumidity sensor418 may be purged by venting the space through theventing lumen435 as described in more detail below. The space may also be flushed by instilling fluids into the space through theinstillation lumen433. As indicated above, thehumidity sensor418 may further comprise a temperature sensor (not shown) as the location within thefluid pathway445 is well-suited to achieve accurate readings of the temperature of the fluids. In some embodiments, thehumidity sensor418 that comprises a temperature sensor may be a single integrated device such as, for example, Model TE HTU21D(F) humidity sensor also available from TE Connectivity.

Referring now toFIGS.9A and9B, thepH sensor420 may comprise a sensing portion disposed within thetherapy cavity403 that is electrically coupled through thecircuit board432 to a front-end amplifier421 mounted on the other side of thecircuit board432 within thecomponent cavity404. The front-end amplifier421 comprises analog signal conditioning circuitry that includes sensitive analog amplifiers such as, for example, operational amplifiers, filters, and application-specific integrated circuits. The front-end amplifier421 measures minute voltage potential changes provided by the sensing portions to provide an output signal indicative of the pH of the fluids. The sensing portion of thepH sensor420 may be fluidly coupled to the space within thetherapy cavity403 by being positioned in thefluid pathway445 that extends into thenegative pressure lumen430 as described above to sense the pH changes. The sensing portion of thepH sensor420 may be formed and positioned within thefluid pathway445 so that the sensing portion directly contacts the wound fluid without contacting the wound itself so that the sensing portion of thepH sensor420 does not interfere with the wound healing process. In some embodiments, the space within thetherapy cavity403 adjacent the sensing portion of thepH sensor420 also may be purged by venting the space through theventing lumen435 as described in more detail below. The space may also be flushed by instilling fluids into the space through theinstillation lumen433. In some embodiments, thepH sensor420 may be, for example,pH sensor450 shown inFIG.9A that comprises a pair of printed medical electrodes including a workingelectrode451 and areference electrode452. In some embodiments, the workingelectrode451 may have a node being substantially circular in shape at one end and having a terminal portion at the other end, and thereference electrode452 may have a node being substantially semicircular in shape and disposed around the node of the workingelectrode451.

In some example embodiments, the workingelectrode451 may comprise a material selected from a group including graphene oxide ink, conductive carbon, carbon nanotube inks, silver, nano-silver, silver chloride ink, gold, nano-gold, gold-based ink, metal oxides, conductive polymers, or a combination thereof. This workingelectrode451 further comprise a coating or film applied over the material wherein such coating or film may be selected from a group including metal oxides such as, for example, tungsten, platinum, iridium, ruthenium, and antimony oxides, or a group of conductive polymers such as polyaniline and others so that the conductivity of the workingelectrode451 changes based on changes in hydrogen ion concentration of the fluids being measured or sampled. In some example embodiments, thereference electrode452 may comprise a material selected from a group including silver, nano-silver, silver chloride ink, or a combination thereof. ThepH sensor450 may further comprise acoating453 covering the electrodes that insulates and isolates the workingelectrode451 from thereference electrode452 except in the electricalconductive space454. In some embodiments, thecoating453 does not completely cover the terminal portions of the workingelectrode451 and thereference electrode452 andform terminals455 and456, respectively. Theterminals455 and456 may be electrically coupled to the front-end amplifier421. In some embodiments, theterminals455 and456 may be electrically coupled to the front-end amplifier421.

In some example embodiments, the terminal portion of the workingelectrode451 and thereference electrode452 may extend through thecircuit board432 and electrically coupled to the front-end amplifier421 of thepH sensor450. As indicated above, the front-end amplifier421 of thepH sensor450 measures minute potential changes between the workingelectrode451 and thereference electrode452 that result from a change in hydrogen ion concentration of the wound fluid as the pH of the wound fluid changes. The front-end amplifier421 may be, for example, an extremely accurate voltmeter that measures the voltage potential between the workingelectrode451 and thereference electrode452. The front-end amplifier421 may be for example a high impedance analog front-end (AFE) device such as the LMP7721 and LMP91200 chips that are available from manufacturers such as Texas Instruments or the AD7793 and AD8603 chips that are available from manufacturers such as Analog Devices.

In some other embodiments, thepH sensor420 may include a third electrode such as, for example,pH sensor460 shown inFIG.9B that comprises a third electrode or acounter electrode462 in addition to the workingelectrode451 and thereference electrode452 of thepH sensor450. Thecounter electrode462 also comprises a node partially surrounding the node of the workingelectrode451 and a terminal466 adapted to be electrically coupled to the front-end amplifier421. Otherwise, thepH sensor460 is substantially similar to thepH sensor450 described above as indicated by the reference numerals. Thecounter electrode462 is also separated from the workingelectrode451 and is also insulated from the wound fluid and the other electrodes by thecoating453 except in the electricalconductive space454. Thecounter electrode462 may be used in connection with the workingelectrode451 and thereference electrode452 for the purpose of error correction of the voltages being measured. For example, thecounter electrode462 may possess the same voltage potential as the potential of the workingelectrode451 except with an opposite sign so that any electrochemical process affecting the workingelectrode451 will be accompanied by an opposite electrochemical process on thecounter electrode462. Although voltage measurements are still being taken between the workingelectrode451 and thereference electrode452 by the analog front end device of thepH sensor460, thecounter electrode462 may be used for such error correction and may also be used for current readings associated with the voltage measurements. Custom printed electrodes assembled in conjunction with a front-end amplifier may be used to partially comprise pH sensors such as thepH sensor450 and thepH sensor460 may be available from several companies such as, for example, GSI Technologies, Inc. and Dropsens.

The systems, apparatuses, and methods described herein may provide other significant advantages. For example, some therapy systems are a closed system wherein the pneumatic pathway is not vented to ambient air, but rather controlled by varying the supply pressure (SP) to achieve the desired target pressure (TP) in a continuous pressure mode, an intermittent pressure mode, or a variable target pressure mode as described above in more detail with reference toFIGS.2A and2B. In some embodiments of the closed system, the wound pressure (WP) being measured in thedressing interface107 may not drop in response to a decrease in the supply pressure (SP) as a result of a blockage within the dressinginterface107 or other portions of the pneumatic pathway. In some embodiments of the closed system, the supply pressure (SP) may not provide airflow to thetissue interface108 frequently enough that may result in the creation of a significant head pressure or blockages within the dressinginterface107 that also would interfere with sensor measurements being taken by the dressinginterface400 as described above. The head pressure in some embodiments may be defined as a difference in pressure (DP) between a negative pressure set by a user or caregiver for treatment, i.e., the target pressure (TP), and the negative pressure provided by a negative pressure source that is necessary to offset the pressure drop inherent in the fluid conductors, i.e., the supply pressure (SP), in order to achieve or reach the target pressure (TP). For example, the head pressure that a negative pressure source needs to overcome may be as much as 75 mmHg. Problems may occur in such closed systems when a blockage occurs in the pneumatic pathway of the fluid conductors that causes the negative pressure source to increase to a value above the normal supply pressure (SP) as a result of the blockage. For example, if the blockage suddenly clears, the instantaneous change in the pressure being supplied may cause harm to the tissue site.

Some therapy systems have attempted to compensate for head pressure by introducing a supply of ambient air flow into the therapeutic environment, e.g., thetherapy cavity403, by providing a vent with a filter on thehousing401 of the dressinginterface400 to provide ambient air flow into the therapeutic environment as a controlled leak. However, in some embodiments, the filter may be blocked when the interface dressing is applied to the tissue site or when asked at least blocked during use. Locating the filter in such a location may also be problematic because it is more likely to be contaminated or compromised by other chemicals and agents associated with treatment utilizing instillation fluids that could adversely affect the performance of the filter and the vent itself.

The embodiments of the therapy systems described herein overcome the problems associated with having a large head pressure in a closed pneumatic environment, and the problems associated with using a vent disposed on or adjacent the dressing interface. More specifically, the embodiments of the therapy systems described above comprise a pressure sensor, such as thepressure sensor416, disposed within the pneumatic environment, i.e., in situ, that independently measures the wound pressure (WP) within thetherapy cavity403 of thehousing401 as described above rather than doing so remotely. Consequently, thepressure sensor416 is able to instantaneously identify dangerously high head pressures and/or blockages within thetherapy cavity403 adjacent themanifold408. Because the auxiliary lumens are not being used for pressure sensing, theventing lumen435 may be fluidly coupled to a fluid regulator such as, for example, thevent regulator118 inFIG.1, that may remotely vent the therapeutic environment within thetherapy cavity403 to the ambient environment or fluidly couple the therapeutic environment to a source of positive pressure. Thevent regulator118 may then be used to provide ambient air or positive pressure to the therapeutic environment in a controlled fashion to “purge” the therapeutic environment within both thetherapy cavity403 and thenegative pressure lumen430 to resolve the problems identified above regarding head pressures and blockages, and to facilitate the continuation of temperature, humidity, and pH measurements as described above.

Using a regulator to purge the therapeutic environment is especially important in therapy systems such as those disclosed inFIGS.1 and3 that provide both negative pressure therapy and instillation therapy for delivering therapeutic fluids to a tissue site. For example, in one embodiment, therapeutic fluid may be instilled to thetissue site150 by applying a negative pressure from the negative-pressure source104 to reduce the pressure at thetissue site150 to draw the therapeutic fluid into the dressing102 as indicated at302. In another embodiment, therapeutic fluid may be instilled to thetissue site150 by applying a positive pressure from the negative-pressure source104 (not shown) or theinstillation pump116 to force the therapeutic fluid from thesolution source114 to thetissue interface108 as indicated at304. Such embodiments may not be sufficient to remove all the therapeutic fluid from the therapeutic environment, or may not be sufficient to remove the therapeutic fluid quickly enough from the therapeutic environment to facilitate the continuation of accurate temperature, humidity, and pH measurements. Thus, theventing lumen435 may be used to provide ambient air or positive pressure to the therapeutic environment to more completely or quickly purge the therapeutic environment to obtain the desired measurements as described above.

In embodiments of therapy systems that include an air flow regulator comprising a valve such as the solenoid valve described above, the valve provides controlled airflow venting or positive pressure to thetherapy cavity403 as opposed to a constant airflow provided by a closed system or an open system including a filter in response to the wound pressure (WP) being sensed by thepressure sensor416. Thecontroller110 may be programmed to periodically open the solenoid valve as described above allowing ambient air to flow into thetherapy cavity403, or applying a positive pressure into thetherapy cavity403, at a predetermined flow rate and/or for a predetermined duration of time to purge the pneumatic system including thetherapy cavity403 and thenegative pressure lumen430 of bodily liquids and exudates so that thehumidity sensor418 and thepH sensor420 provide more accurate readings and in a timely fashion. This feature allows the controller to activate the solenoid valve in a predetermined fashion to purge blockages and excess liquids that may develop in the fluid pathways or thetherapy cavity403 during operation. In some embodiments, the controller may be programmed to open the solenoid valve for a fixed period of time at predetermined intervals such as, for example, for five seconds every four minutes to mitigate the formation of any blockages.

In some other embodiments, the controller may be programmed to open the solenoid valve in response to a stimulus within the pneumatic system rather than, or additionally, being programmed to function on a predetermined therapy schedule. For example, if the pressure sensor is not detecting pressure decay in the canister, this may be indicative of a column of fluid forming in the fluid pathway or the presence of a blockage in the fluid pathway. Likewise, the controller may be programmed to recognize that an expected drop in canister pressure as a result of the valve opening may be an indication that the fluid pathway is open. The controller may be programmed to conduct such tests automatically and routinely during therapy so that the patient or caregiver can be forewarned of an impending blockage. The controller may also be programmed to detect a relation between the extent of the deviation in canister pressure resulting from the opening of the valve and the volume of fluid with in the fluid pathway. For example, if the pressure change within the canister is significant when measured, this could be an indication that there is a significant volume of fluid within the fluid pathway. However, if the pressure change within the canister is not significant, this could be an indication that the plenum volume was larger.

The systems, apparatuses, and methods described herein may provide additional advantages related to the instillation of cleansing and/or therapeutic solutions to thetherapy cavity403. Using a source of fluids such as, for example,solution source114 to flush the therapeutic environment is especially important in therapy systems such as those disclosed inFIGS.1 and3 that provide both negative pressure therapy and instillation therapy for delivering therapeutic fluids to a tissue site. For example, the sensors are disposed within thetherapy cavity403 and consequently exposed and in direct conflict with wound fluids and exudates that have the potential for fouling the sensors so that they do not provide reliable data over a period of time during which therapy is being provided. Moreover, fouling the sensors may also disable the sensors and/or degrade the calibration of the sensors such that they no longer accurately analyze the wound fluid to provide data indicating the current state of the wound. Additionally, some of the sensors such as, for example, thepH sensor420 comprising screen-printed electrodes as described above require soaking or hydration to ensure stable measurement of the potential difference between the electrodes, i.e., the voltage between the working and the reference electrodes. Manual cleaning or hydration (lavage) of the sensors would not work because the therapeutic cavity would not be conveniently accessible as it would require the removal of the dressing to provide sufficient access to thetissue interface108. Thus, the ability to provide cleansing and/or therapeutic solutions directly to thetherapy cavity403 for cleansing or hydration as described above along with the ability to deliver negative pressure and other pH-modulating controlled instillates such as phosphate buffered saline or weak acidic acids is a distinct advantage to enhance operation of the systems and methods described herein.

As described above in more detail, some embodiments of thetherapy system100 may include a solution source, such assolution source114, without an instillation pump, such as theinstillation pump116. Instead, thesolution source114 may be fluidly coupled directly or indirectly to thedressing interface400, and may further include theinstillation regulator115 electrically coupled to thecontroller110 as described above. In operation, thenegative pressure source104 may apply negative pressure to thetherapy cavity403 through thecontainer112 and thenegative pressure lumen430 to create a vacuum within the space formed by thetherapy cavity403 and thetissue interface108. The vacuum within the space would draw cleansing and/or hydration fluid from thesolution source114 and through theinstillation lumen433 into the space for cleansing or wetting the sensors and/or thetissue interface108. In some embodiments, thecontroller110 may be programmed to modulate theinstillation regulator115 to control the flow of such fluids into the space. Any of the embodiments described above may be utilized to periodically clean, rinse, or hydrate the sensors, the tissue interface, and the tissue site using saline along with other pH-modulating instillation fluids such as weak acidic acids.

Referring now toFIGS.10A and10B, a second dressing is shown comprising adressing interface500 that may be substantially similar to thefirst dressing interface400 as indicated in part by the last two digits of the reference numerals identifying various components of thesecond dressing interface500 as antecedent basis if not described differently below. Thesecond dressing interface500 may be a lower profile embodiment of thefirst dressing interface400 because thesecond dressing interface500 does not include a neck portion similar to theneck407 that angles upwardly away from thetissue site410. Eliminating the neck portion allows theconduit405 to be coupled to thesecond dressing interface500 parallel to thetissue site410. Otherwise, like thefirst dressing interface400, the dressinginterface500 may comprise ahousing501 and awall502 disposed within thehousing501 wherein thewall502 forms atherapy cavity503 that opens to the manifold408 when disposed at thetissue site410 and acomponent cavity504 opening away from thetissue site410 of the upper portion of the dressinginterface500. In some embodiments, sensing portions of various sensors may be disposed within thetherapy cavity503, and electrical devices associated with the sensors may be disposed within thecomponent cavity504 and electrically coupled to the sensing portions through thewall502. Electrical devices disposed within thecomponent cavity504 may include components associated with some example embodiments of the therapy system ofFIG.1 as described above. The dressinginterface500 further comprises the sensor assembly525 including all of the sensors and the associated electrical devices that have been described in more detail above with respect to thefirst dressing interface400 as indicated by the reference numerals.

In some embodiments, thesecond dressing interface500 may differ further from thefirst dressing interface400. For example, thehousing501 may comprise several pieces including ahousing body570 having walls that may have a generally cylindrical shape including aproximal wall section571 and adistal wall section572. Theproximal wall section571 may comprise aproximal bracket573 and thedistal wall section572 may comprise adistal bracket574 that support the sensor assembly525. Thesecond dressing interface500 may differ further from thefirst dressing interface400 because it may comprise two separate ports to accommodate two separate conduits,conduit505 andconduit555, rather than asingle conduit405 that includes a primary and auxiliary lumens. In some embodiments, theconduit505 may include anegative pressure lumen530 fluidly coupled to thenegative pressure source104 through thecontainer112 for delivering negative pressure to thetherapy cavity503 as indicated byarrow531. In some embodiments, theconduit555 may include and aninstillation lumen533 fluidly coupled to theinstillation source114 for delivery of cleansing and/or instillation fluids as indicated byarrow534. Theproximal wall section571 may further comprise a negative-pressure port576 configured to be fluidly coupled to thenegative pressure lumen530 of theconduit505, and aport577 configured to be fluidly coupled to theinstillation lumen533 of theconduit555.

In some embodiments, thehousing501 may further comprise a flange portion such as, for example, aflange509, that is the terminus of thehousing501 adapted to contact and provide a seal over the manifold408 thereby forming thetherapy cavity503. Because thehousing501 may comprise several pieces, each piece of thehousing501 may further comprise a portion of theflange509 in some example embodiments. The second dressing may further comprise adrape ring513 covering the circumference of theflange509 and the adjacent portion of thedrape406 to better seal thetherapy cavity503 of thehousing501 over the manifold408 and thetissue site410.

Thesecond dressing interface500 may differ further from thefirst dressing interface400 because thehousing501 may further comprise shaped features or baffles disposed within thetherapy cavity503 and operatively disposed adjacent theport576 and theport577 to direct the flow of the instillation fluids on fluid delivery and removal pathways to adequately clean and/or hydrate the sensors as described in more detail above. In some embodiments, thehousing501 may further comprisedirectional baffles581 and583 extending from the wall of theproximal wall section571 towards thedistal wall section572 on either side of the of the ports to direct the flow of fluids along the fluid delivery and removal pathways under both vacuum and instillation conditions such that the sensors are exposed to the flow of fluids. In some embodiments, thehousing501 may further comprise aseparation baffle582 extending from the wall of theproximal wall section571 towards thedistal wall section572 and between the of the ports to separate the initial delivery of fluid adjacent theport577 from the final removal of fluid adjacent theport576 so that the flow of fluid reaches the sensors rather than being prematurely drained form thetherapy cavity503. For example, this embodiment is effective to adequately hydrate thepH sensor520 to ensure that thepH sensor520 is always exposed to the flow of fluids and that thepH sensor520 can be pre-soaked to immediately measure the acidity of fluids from the tissue site.

Referring now toFIGS.11A and11B, another example embodiment of the dressinginterface500 is shown that differs from the embodiment shown inFIGS.10A and10B because thedressing interface500 comprises a third port to accommodate a conduit having a venting lumen that may be fluidly coupled to thevent regulator118 for purging fluids from thetherapy cavity403. In some embodiments, the conduit may be separate from theconduit505 and theconduit555 and fluidly coupled to the third port. In other embodiments, the conduit may be configured in a side-by-side configuration with either one, or both, of the other two conduits. In yet other embodiments, the conduit may be configured with two lumens that include the venting lumen and either one, or both, of the other two lumens. For example, aconduit655 has aventing lumen633 and is configured in a side-by-side configuration withnegative pressure conduit505. Theventing lumen633 may be fluidly coupled to athird port678 that extends through theproximal wall section571. In some embodiments, thethird port678 may extend through thebaffle581 so that thethird port678 opens closer to thedistal wall section572 to enhance the removal of fluids from thetherapy cavity503 as described in more detail above. In some embodiments, theport678 may comprise a separate conduit extending from theproximal wall section571 toward the wall of thedistal wall section572. In operation, theventing lumen633 is similar to thevent conduit145 that may be fluidly coupled to thevent regulator118 for purging fluids from thetherapy cavity503 as indicated byarrow636. Theinstillation lumen533 may be fluidly coupled to theinstillation source114 for delivery of cleansing and/or instillation fluids to thetherapy cavity503 as indicated byarrow534. Theport577 may be configured to be fluidly coupled to theinstillation lumen533 of theconduit555. Theinstillation lumen533 is similar to theinstillation conduit133 that may be fluidly coupled directly or indirectly to thesolution source114 for flushing and removing fluids from thetherapy cavity403 by simultaneously applying negative pressure through thenegative pressure lumen530.

Referring back toFIGS.10A and10B, thecomponent cavity504 containing the electrical devices in some embodiments may be open to the ambient environment such that the electrical devices are exposed to the ambient environment. Thecomponent cavity504 of the dressinginterface500 unlike the dressinginterface400 may already be closed by as integral portion of thehousing body570 and, as such, may not require a cover such as, for example, thecap411 to protect the electrical devices. In some other embodiments, the upper portion of thehousing body570 may comprise an opening for access to the electrical devices, wherein the opening is covered by acover511 to close thecomponent cavity504. In some example embodiments, thecomponent cavity504 may still be vented to the ambient environment to provide cooling and access to the electrical devices if needed. In some other example embodiments, thecomponent cavity504 may be vented to the ambient environment to provide a source of ambient pressure and/or humidity for thepressure sensor516 and/or thehumidity sensor518 for comparison to the pressure and humidity within thetherapy cavity503 as described above.

More specifically, thepressure sensor516, the temperature andhumidity sensor518, and thepH sensor520 may be disposed in thehousing501 with each one having a sensing portion disposed in thetherapy cavity503 of thehousing501 and associated electronics or outputs extending into thecomponent cavity504. In some example embodiments, the sensors may be coupled to or mounted on thewall502 and electrically coupled to electrical components and circuits such as, for example, a microprocessor disposed within thecomponent cavity504 by electrical conductors extending through thewall502. In some preferred embodiments, the electrical conductors extend through pathways in thewall502 while keeping thetherapy cavity503 electrically and pneumatically isolated from thecomponent cavity504. In this example embodiment, the circuit board532 may be thewall502 that separates thetherapy cavity503 from thecomponent cavity504. In some other embodiments, thewall502 may comprise a sintered polymer that is highly hydrophobic and molded within thehousing501. Essentially, thepolymeric wall502 would effectively function as a large filter to hermetically isolate thecomponent cavity504 from thetherapy cavity503 and the wound fluids being drawn in through themanifold408.

In some embodiments, the electrical circuits and/or components associated with the sensors that are mounted on the circuit board532 within thecomponent cavity504 may be electrically coupled to thecontroller110 to interface with the rest of thetherapy system100 as described above. In some embodiments, thecommunications module522 may be disposed in thecomponent cavity504 of thehousing501 and mounted on the circuit board532 within thecomponent cavity504. For example, the electrical circuits and/or components associated with the sensors along with the terminal portion of the sensors may be electrically coupled to thecontroller110 by wireless means such as an integrated device implementing Bluetooth® Low Energy wireless technology.

In some embodiments, thepower source524 may be disposed within thecomponent cavity504 of thehousing501, mounted on the circuit board532, and secured in place to the circuit board532 by abracket526. Thepower source524 may be, for example, a battery that provides a 3-volt source for thecommunications module522 and the other electronic components within thecomponent cavity504 associated with the sensors. In some example embodiments, the sensors, the electrical circuits and/or components associated with the sensors, thewall502 and/or the circuit board532, thecommunications module522, and thepower source524 may be integrated as components of the sensor assembly525. In some preferred embodiments, thewall502 of the sensor assembly525 may be the circuit board532 as described above that provides a seal betweentissue site410 and the atmosphere when positioned over the opening between thetherapy cavity503 and thecomponent cavity504 of thehousing501.

Each of the sensors may comprise a sensing portion extending into thetherapy cavity503 of thehousing501 and a terminal portion electrically coupled to the electrical circuits and/or components within thecomponent cavity504. Thepressure sensor516 may be disposed on the circuit board532 within thetherapy cavity503 of the sensor assembly525 that provides a seal betweentissue site410 and the atmosphere as described above. In some embodiments, thepressure sensor516 may be a differential gauge comprising asensing portion542 and a terminal portion or vent543. Thevent543 of thepressure sensor516 may be fluidly coupled through the circuit board532 to thecomponent cavity504 and the ambient environment by avent hole544 extending through the circuit board532. Thesensing portion542 of thepressure sensor516 may be positioned in close proximity to the manifold408 to optimize fluid coupling and accurately measure the wound pressure (WP) at thetissue site410.

In some embodiments, thehumidity sensor518 may comprise a temperature sensor for measuring the temperature at thetissue site410. Thehumidity sensor518 may also be supported on the circuit board532 of the sensor assembly525. In some embodiments, thehumidity sensor518 may comprise a sensing portion that is electrically coupled through the circuit board532 to a microprocessor disposed within thecomponent cavity504. The sensing portion of thehumidity sensor518 may be disposed within thetherapy cavity503 that includes afluid pathway545 extending from theport577 to theport576 represented by a series of dashed arrows and further represented by thearrow534 and thearrow531, respectively, to sense both the humidity and the temperature. The sensing portion of thehumidity sensor518 may be positioned within thefluid pathway545 to limit direct contact with bodily fluids being drawn into thenegative pressure lumen530 from thetissue site410 and to enhance exposure to the cleansing fluids from theinstillation lumen533.

In some embodiments, thehumidity sensor518 also may comprise a second humidity sensor (not shown) that may be fluidly coupled to thecomponent cavity504 through avent hole541 extending through the circuit board532 to sense the ambient environment within thecomponent cavity504. Alternatively, the sensor assembly525 may further comprise asecond humidity sensor519 having a sensing portion disposed within thecomponent cavity504 on thewall502 and electrically coupled to electrical components and circuits such as, for example, a microprocessor also disposed within thecomponent cavity504. Thesecond humidity sensor519 also may comprise a temperature sensor component. Thus, thesecond humidity sensor519 may be configured to sense the relative humidity of the ambient environment within thecomponent cavity504 for comparison to the relative humidity of the therapeutic environment within thetherapy cavity503 sensed by thehumidity sensor518. Sensing a differential humidity from such comparisons may offer a number of advantages such as, for example, enhanced leak detection that distinguishes the type of leak occurring, full dressing determinations (automated fill assist), and enhanced the blockage detection, all of such advantages disclosed in Provisional Application No. 62/617,517 filed Jan. 15, 2018, which is incorporated herein by reference.

ThepH sensor520 also may comprise a sensing portion disposed within thetherapy cavity503 that is electrically coupled through the circuit board532 to an analog front end device mounted on the other side of the circuit board532 within thecomponent cavity504. The analog front end device measures minute voltage potential changes provided by the sensing portion. The sensing portion of thepH sensor520 may be fluidly coupled to the space within thetherapy cavity503 by being positioned in thefluid pathway545 that extends into thenegative pressure lumen530 as described above. The sensing portion of thepH sensor520 may be formed and positioned within thefluid pathway545 so that the sensing portion directly contacts the wound fluid without contacting the wound itself so that the sensing portion of thepH sensor520 does not interfere with the wound healing process. In some embodiments, thepH sensor520 may be, for example, thepH sensor450 shown inFIG.9A that comprises a pair of printed medical electrodes including a workingelectrode451 and areference electrode452 as more fully described above. In some other embodiments, thepH sensor520 may include a third electrode such as, for example, thepH sensor460 shown inFIG.9B that comprises a third electrode or acounter electrode462 in addition to the workingelectrode451 and thereference electrode452 of thepH sensor450 as more fully described above. The sensing portion of thepH sensor520 also may be positioned within thefluid pathway545 to enhance exposure to the fluids from theinstillation lumen533 for the necessary cleansing and hydration. In the embodiments described above, the sensing portion of thepH sensors420 and520 when used with the combination of negative pressure and instillation, relies on using the vacuum induced flow created in thetherapeutic cavities403 and503 to expose the sensing portion to wound fluids for measurement when wound fluids are being removed from the cavity and then using the instillation of cleansing fluids to clean and hydrate the sensing portion in order to recalibrate the pH sensors during routine instillation therapy procedures. The pH sensors may also be used along with other sensors to determine the type of fluid being instilled into the therapy cavity to prevent incorrect fluids from being delivered to, or left within, the therapy cavity, and then transmit a signal to thecontroller110 that shuts down or overrides the delivery system upon detection. For example, the pH sensor may detect fluids that do not correspond to the correct pH value and upon detection overrides the delivery system.

In some embodiments where thecomponent cavity504 is covered or sealed, thecomponent cavity504 may be vented to the ambient environment to provide cooling and access to the electrical devices if needed. Thecomponent cavity504 may also be vented to the ambient environment in order to provide a source of ambient pressure for thepressure sensor516 and a source of ambient humidity for thesecond humidity sensor519 that can be used for comparison to the pressure and relative humidity within thetherapy cavity503 as described above. In such embodiments, access to the ambient environment may be provided by venting the upper portion of the dressinginterface500 itself. However, the dressinginterface500 is fixed to the manifold408 at the tissue site, so it is possible that the user or caregiver may inadvertently block venting to thecomponent cavity504 while adjusting the drape such as, for example, thecover106. Additionally, the user or patient may inadvertently sit or lay on thedressing interface500 that may also block venting to thecomponent cavity504. In both cases, blocking access to the ambient environment could cause the electrical devices to overheat resulting in erroneous reading communications within the system or cause the sensors to provide erroneous readings detrimental to the patient. Therefore, in some embodiments it may be desirable to modify thecomponent cavity504 by sealing thecomponent cavity504 to form an ambient chamber within the dressinginterface500 and providing a port coupled to the ambient chamber that may be coupled to an ambient conduit extending to a location sufficiently distant from the dressinginterface500 and the tissue site to avoid such mishaps. Such embodiments provide remote access to the ambient environment that may enhance the performance and safety of the dressinginterface500 by providing more consistent readings and data for promoting healing at the tissue site.

Referring again toFIGS.11A and11B, another example embodiment of the dressinginterface500 is shown that differs from the embodiment shown inFIGS.10A and10B to the extent that thecomponent cavity504 is sealed to form anambient chamber604 and further comprises anambient port578 that may be fluidly coupled to anambient conduit585. In some embodiments, theambient conduit585 may comprise anambient lumen590 fluidly coupled to theambient chamber604 for providing remote access to the ambient environment as indicated by thearrow591. In some embodiments, theambient conduit585 may be separate from theconduit505 and fluidly coupled to theambient port578. In other embodiments, theambient conduit585 may be configured in a side-by-side configuration with theconduit505 to form a single conduit. In some embodiments, the other end of theambient conduit585 may be coupled to the ambient environment by an in-line connector that fluidly couples the dressinginterface500 to thecontainer112 as shown inFIG.1 to provide a source of air from the ambient environment to theambient chamber604. In some embodiments, the in-line connector may provide air from the ambient environment that provides an accurate indication of the ambient pressure and humidity provided by thepressure sensor516 and thesecond humidity sensor519 for comparison to the pressure and humidity within thetherapy cavity503 provided by thepressure sensor516 and thehumidity sensor518, respectively, that are fluidly coupled to thetherapy cavity503.

Referring toFIG.12, a schematic diagram of fluid conduits coupling thedressing interface500 to thecontainer112 including an in-line connector690 is shown, and in some embodiments may be associated with some embodiments of the dressing interfaces shown inFIGS.1,4,10A and11A for providing negative pressure and/or instillation therapy. In some embodiments, the in-line connector690 may comprise two connector parts that mate together including afirst connector part691 and asecond connector part692. In some example embodiments, thefirst connector part691 may be fluidly coupled to thenegative pressure conduit135 coupled to thecontainer112 and/or theventing conduit145 coupled to theregulator118. In some example embodiments, thesecond connector part692 may be fluidly coupled to thenegative pressure conduit505 and/or thevent conduit655 which are fluidly coupled to their corresponding conduits, i.e., thenegative pressure conduit135 and theventing conduit145, respectively, when the two parts are connected to each other.

In some example embodiments, thesecond connector part692 also may have an internal chamber including an orifice orport693 open to the ambient environment that may be fluidly coupled to theambient lumen590 of theambient conduit585 which in some embodiments may terminate at the internal chamber within thesecond connector part692. The orifice orport693 may be located at the side of thesecond connector part692 to minimize the possibility that the orifice may be covered or occluded inadvertently as a result of the patient or user laying on the in-line connector690. In some embodiments, thesecond connector part692 may further comprise afilter694 that covers the orifice orport693 prevent fluid ingress into theambient lumen590. Because theambient chamber604 is sealed and not in fluid communication with thetherapy cavity503, thefilter694 would not necessarily need to be a bacterial filter for protecting theambient lumen590 from contamination by bacteria or other particles. Thus, theambient conduit585 and theport693 provide theambient chamber604 with access to the ambient environment at a location removed from the dressinginterface500 to help prevent the loss of access to the ambient environment.

In some alternative example embodiments not shown inFIG.12, the other end of theambient conduit585 may be coupled to the ambient environment by the in-line connector690 and anotherambient conduit185 that terminates proximate thecontainer112 to provide theambient chamber604 with access to the ambient environment from a location even further removed from the dressinginterface500 and the in-line connector690. In some embodiments, theambient conduit185 rather than thesecond connector part692 may comprise an orifice (not shown) proximate thecontainer112 that provides access to the ambient environment, and also may be covered by a filter to prevent fluid ingress as described above. Thesecond connector part692 may be fluidly coupled in a similar fashion to the embodiment shown inFIG.12 wherein thenegative pressure conduit505 and/or thevent conduit655 are fluidly coupled to their corresponding conduits, i.e., thenegative pressure conduit135 and theventing conduit145, respectively, when the two parts are connected to each other. Providing access to the ambient environment from a location of theambient conduit185 proximate thecontainer112 may further reduce the possibility that the orifice might be covered or occluded by the patient or caregiver. For example, it will be less likely that a patient might inadvertently roll over a container or the device to which it is attached because the container and/or the device is normally larger than an in-line connector.

In some embodiments, thenegative pressure conduit505, theambient conduit585 and thevent conduit655 may be structured as separate conduits as shown inFIG.12. In some other embodiments, thenegative pressure conduit505, theambient conduit585 and thevent conduit655 may be bundled into other multiple or single embodiments such as, for example, aconnector conduit695 that includes the functionality of all three conduits. Referring more specifically toFIG.13A, theconnector conduit695 is a single conduit comprising three separate lumens including thenegative pressure lumen530, theambient lumen590, and thevent lumen633, that may be substituted for the three separate conduits. Referring toFIG.13B, theconnector conduit695 may be modified as conduit697 to further comprise theinstillation lumen533 rather than having a separate instillation conduit such as, for example, theinstillation conduit555 as shown inFIG.10B.

In operation, thetissue interface108 may be placed within, over, on, or otherwise proximate a tissue site, such astissue site150 as shown inFIG.4. Thecover106 may be placed over thetissue interface108 and sealed to an attachment surface near thetissue site150. For example, thecover106 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing102 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source104 can reduce the pressure in the sealed therapeutic environment.

Some embodiments of therapy systems including, for example, thetherapy system100 including thedressing interface400 and thedressing interface500, are illustrative of a method for applying fluids to a tissue interface and sensing a property of a fluid at a tissue site for treating the tissue site. For example, the method may comprise positioning a dressing interface on the tissue site, the dressing interface having a housing having a body including a therapy cavity and a component chamber fluidly isolated from the therapy cavity, the therapy cavity having an opening configured to be in fluid communication with the tissue interface, and a control device disposed within the component chamber. The method may further comprise providing the component chamber with access to the ambient environment through an ambient port to a sensor disposed within the therapy cavity and coupled to the control device. The method also comprises applying negative pressure to the therapy cavity through a negative-pressure port to draw fluids from the tissue interface and into the therapy cavity. The method may also comprise sensing the property of the fluid within the therapy cavity with the sensor, and then providing a property signal to the control device indicative of the property of the fluid relative to the corresponding property of the ambient environment.

Some other embodiments of therapy systems including, for example, thetherapy system100 including thedressing interface400 and thedressing interface500, are illustrative of a method for providing reduced-pressure to a tissue interface and sensing properties of fluids extracted from a tissue site for treating the tissue. In one example embodiment, the method may comprise positioning a housing of a dressing interface having an aperture in fluid communication with the tissue interface disposed adjacent the tissue site. The dressing interface may comprise a wall disposed within the housing to form a therapy cavity within the housing and a component cavity fluidly sealed from the therapy cavity, wherein the therapy cavity opens to the aperture. Such dressing interface may further comprise a reduced-pressure port fluidly coupled to the therapy cavity and adapted to be fluidly coupled to a reduced-pressure source, and a control device disposed in the component cavity. The dressing interface may further comprise a pH sensor, a temperature sensor, a humidity sensor, and a pressure sensor, each having a sensing portion disposed within the therapy cavity and each electrically coupled to the control device through the wall. The method may further comprise applying reduced pressure to the therapy cavity to draw fluids from the tissue interface into the therapy cavity and out of the reduced-pressure port. The method may further comprise sensing the pH, temperature, humidity, and pressure properties of the fluids flowing through therapy cavity utilizing the sensing portion of the sensors and outputting signals from the sensors to the control device. The method may further comprise providing fluid data from the control device indicative of such properties, and inputting the fluid data from the control device to the therapy system for processing the fluid data and treating the tissue site in response to the fluid data.

The systems, apparatuses, and methods described herein may provide other significant advantages over dressing interfaces currently available. For example, a patient may require two dressing interfaces for two tissue sites, but wish to use only a single therapy device to provide negative pressure to and collect fluids from the multiple dressing interfaces to minimize the cost of therapy. In some therapy systems currently available, the two dressing interfaces would be fluidly coupled to the single therapy device by a Y-connector. The problem with this arrangement is that the Y-connector embodiment would not permit the pressure sensor in the therapy device to measure the wound pressure in both dressing interfaces independently from one another. A significant advantage of using a dressing interface including in situ sensors, e.g., the dressinginterface400 including thesensor assembly425 and thepressure sensor416, is that multiple dressings may be fluidly coupled to the therapy unit of a therapy system and independently provide pressure data to the therapy unit regarding the associated dressing interface. Each dressinginterface400 that is fluidly coupled to the therapy unit for providing negative pressure to thetissue interface108 and collecting fluids from thetissue interface108 has the additional advantage of being able to collect and monitor other information at the tissue site, as well as the humidity data, temperature data, and the pH data being provided by the in situ sensors thesensor assembly425. For example, thesensor assembly425 may include accelerometers to determine the patient's compliance with specific therapy treatments including various exercise routines and/or various immobilization requirements.

Another advantage of using thedressing interface400 that includes a pressure sensor in situ such as, for example, thepressure sensor416, is that thepressure sensor416 can more accurately monitor the wound pressure (WP) at the tissue site and identify blockages and fluid leaks that may occur within the therapeutic space as described in more detail above. Another advantage of using a dressing interface including in situ sensors, e.g., the dressinginterface400, is that thesensor assembly425 provides additional data including pressure, temperature, humidity, and pH of the fluids being drawn from the tissue site that facilitates improved control algorithms and wound profiling to further assist the caregiver with additional information provided by the therapy unit of the therapy system to optimize the wound therapy being provided and the overall healing progression of the tissue site when combined with appropriate control logic.

The disposable elements can be combined with the mechanical elements in a variety of different ways to provide therapy. For example, in some embodiments, the disposable and mechanical systems can be combined inline, externally mounted, or internally mounted. In another example, the dressinginterface400 may be a disposable element that is fluidly coupled to a therapy unit of a therapy system as described in more detail above.

While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications. For example, certain features, elements, or aspects described in the context of one example embodiment may be omitted, substituted, or combined with features, elements, and aspects of other example embodiments. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles “a” or “an” do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing102, thecontainer112, or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, thecontroller110 may also be manufactured, configured, assembled, or sold independently of other components.

The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described herein may also be combined or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims.

Claims (17)

What is claimed is:

1. A dressing interface for connecting a source of fluids to a tissue interface and sensing properties of fluid at a tissue site, the dressing interface comprising:

a housing having a body including a therapy cavity and a component cavity fluidly isolated from the therapy cavity, the therapy cavity having an opening configured to be in fluid communication with the tissue interface;

a negative-pressure port fluidly coupled to the therapy cavity and adapted to be fluidly coupled to a negative-pressure source;

an ambient port fluidly coupled to the component cavity and adapted to be fluidly coupled to an ambient environment;

a controller disposed within the component cavity and including a microprocessor;

at least one sensor electrically coupled to the microprocessor and having a sensing portion disposed within the therapy cavity and a vent portion fluidly coupled to the component cavity through a vent hole; and

a fluid conduit having a first end coupled to the ambient port and a second end.

2. The dressing interface ofclaim 1, further comprising a pH sensor having a sensing portion disposed within the therapy cavity and electrically coupled to the microprocessor.

3. The dressing interface ofclaim 2, further comprising an instillation port fluidly coupled to the therapy cavity and adapted to fluidly couple an instillation source to the tissue interface.

4. The dressing interface ofclaim 3, wherein the sensing portion of the pH sensor is disposed proximate the instillation port.

5. The dressing interface ofclaim 1, wherein the at least one sensor comprises at least one of a temperature sensor and a humidity sensor.

6. The dressing interface ofclaim 5, further comprising an instillation port fluidly coupled to the therapy cavity and adapted to fluidly couple an instillation source to the tissue interface.

7. The dressing interface ofclaim 1, wherein the control device further comprises a wireless transmitter coupled to the microprocessor.

8. The dressing interface ofclaim 1, further comprising a fluid connector having a connector port fluidly coupled to the second end of the fluid conduit and the ambient

environment through an orifice in the fluid connector.

9. The dressing interface ofclaim 8, wherein the fluid connector further comprises a filter disposed between the connector port and the ambient environment.

10. The dressing interface ofclaim 1, wherein the second end is configured to terminate proximate a canister fluidly coupled to the therapy cavity and having an orifice configured to access the ambient environment.

11. The dressing interface ofclaim 1, wherein the second end configured to terminate within a canister fluidly coupled to the therapy cavity and having an orifice covered by a filter and configured to access the ambient environment.

12. The dressing interface ofclaim 1, further comprising a fluid conductor having a first end coupled to the negative-pressure port and the ambient port.

13. The dressing interface ofclaim 1, further comprising a vent port configured to be fluidly coupled to a vent conduit fluidly coupled to the therapy cavity and adapted to enable airflow into the therapy cavity, and a fluid conductor having a first end coupled to the negative-pressure port, the ambient port, and the vent port.

14. The dressing interface ofclaim 13, further comprising a fluid connector having a connector oriface, wherein the fluid conductor has a second end fluidly coupling the ambient port to the connector oriface for sensing properties of the ambient environment.

15. A system for connecting a source of fluids to a tissue interface and sensing properties of fluid at a tissue site, the system comprising:

a dressing interface comprising:

a housing having a body including a therapy cavity and a component chamber fluidly isolated from the therapy cavity, the therapy cavity having an opening configured to be in fluid communication with the tissue interface;

a negative-pressure port fluidly coupled to the therapy cavity;

an ambient port fluidly coupled to the component chamber;

a control device disposed within the component chamber including a microprocessor and a transmitter coupled to the microprocessor; and

at least one sensor having a sensing portion disposed within the therapy cavity and coupled to the microprocessor, and further having an ambient input fluidly coupled to the component chamber for sensing properties of an ambient environment;

a canister adapted to be fluidly coupled to a source of reduced pressure; and

a fluid conductor fluidly coupling the negative-pressure port to the canister, and fluidly coupling the ambient port to the ambient environment.

16. A method of applying negative-pressure to a tissue interface and sensing a property of fluid at a tissue site, the method comprising:

positioning a dressing interface on the tissue site, the dressing interface having a housing having a body including a therapy cavity and a component chamber fluidly isolated from the therapy cavity, the therapy cavity having an opening configured to be in fluid communication with the tissue interface, and a control device disposed within the component chamber;

providing the component chamber with access to an ambient environment through an ambient port to a sensor disposed within the therapy cavity and coupled to the control device;

applying negative pressure to the therapy cavity through a negative-pressure port to draw fluids from the tissue interface and into the therapy cavity;

sensing the property of the fluid within the therapy cavity with the sensor disposed within the therapy cavity;

providing a property signal to the control device indicative of the property of the fluid relative to a corresponding property of the ambient environment;

instilling fluids through an instillation port into the therapy cavity to cleanse the sensor and purging fluids from the therapy cavity; and

sensing pH properties of the fluid within the therapy cavity provided from a pH sensor disposed within the therapy cavity and coupled to the control device, wherein sensing pH properties of the fluid comprises sensing the pH properties of the fluids prior to providing instillation fluids to the therapy cavity.

17. The method ofclaim 16, further comprising sensing the pH properties of the fluids after providing instillation fluids to the therapy cavity.

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